Wireless power supply system, wireless power transmitting device, and wireless power receiving device

• US 8,933,583 B2
• Filed: 09/13/2011
• Issued: 01/13/2015
• Est. Priority Date: 03/30/2009
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Uchida, Akiyoshi
• Primary Examiner(s): Fureman, Jared
• Assistant Examiner(s): Pham, Duc M
• Application Number:
  US13/231,757
• Publication Number:
  US 20120001485A1
• Time in Patent Office: 1,218 Days
• Field of Search: 307/104, 307/11
• US Class Current: 307/11
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge

Abstract

A wireless power supply system includes: a wireless power transmitting device configured to include a variable resonant circuit having a variable-controllable resonant frequency characteristic, and to transmit electric power wirelessly via the variable resonant circuit; a power transmission control unit configured to variably control the resonant frequency characteristic of the variable resonant circuit; and a plurality of wireless power receiving devices configured to include respective unique resonant circuits having respective unique resonant frequency characteristics which are different to each other, and to wirelessly receive power from the wireless power transmitting device by a magnetic field resonance mode arising as a result of the unique resonant circuit tuning to a resonant frequency of the variable resonant circuit.

Claims

1. A wireless power supply system, comprising:

a wireless power transmitting device configured to include a variable resonant circuit including a power transmitting coil and having a variable-controllable resonant frequency characteristic, and to transmit electric power wirelessly via the variable resonant circuit;

an electromagnetic induction coil, which is included in the wireless power transmitting device, configured to separate from the power transmitting coil by physical distance;

a plurality of wireless power receiving devices configured to include respective unique resonant circuits having respective unique resonant frequency characteristics which are different to each other, and to wirelessly receive electric power from the power transmitting coil by a magnetic field resonance mode arising as a result of the unique resonant circuit tuning to a resonant frequency of the variable resonant circuit; and

a communication unit configured to receive information of a resonant frequency transmitted from at least one of the plurality of wireless power receiving devices, and to transmit the received information of the resonant frequency to a power transmission control unit,

wherein the power transmission control unit is configured to variably control the resonant frequency characteristic of the variable resonant circuit by transmitting alternating current power which matches a unique resonant frequency of the at least one of the plurality of wireless power receiving devices from the electromagnetic induction coil to the power transmitting coil by an electromagnetic induction according to the information of the resonant frequency transmitted from the communication unit.

2. The wireless power supply system according to claim 1, wherein:

the variable resonant circuit is configured to include a power transmitting coil and a plurality of capacitors of different capacitances which are selectively connected to the power transmitting coil; and

the power transmission control unit is configured to selectively control connection of the plurality of capacitors to the power transmitting coil.

3. The wireless power supply system according to claim 2, wherein

each of the unique resonant circuits is configured to include a capacitor, capacitance of the respective capacitors being mutually different, and a power receiving coil connected to the capacitor.

4. The wireless power supply system according to claim 1, wherein:

the power transmission control unit, when the communication unit receives a plurality of power transmission requests in an overlapping manner, tunes the alternating current frequency to the resonant frequencies of the corresponding wireless power receiving devices in the order in which the power transmission requests are received or match the resonant frequencies in a cyclical manner by means of time sharing processing.

5. A wireless power supply system, comprising:

a wireless power transmitting unit configured to include a variable resonant circuit including a power transmitting coil capable of transmitting electric power as magnetic field energy, the variable resonant circuit having a characteristic of resonating at a first frequency and a second frequency, and to transmit magnetic field energy from the power transmitting coil in a resonant state;

an electromagnetic induction coil, which is included in the wireless power transmitting device, configured to separate from the power transmitting coil by physical distance;

a first wireless power receiving unit configured to include a first power receiving resonant circuit including a first power receiving coil capable of taking in magnetic field energy, the first power receiving resonant circuit having a characteristic of resonating at the first frequency, and to receive magnetic field energy from the power transmitting coil as electric power by means of the first power receiving coil which resonates with the power transmitting coil and enters a resonant state;

a second wireless power receiving unit configured to include a second power receiving resonant circuit including a second power receiving coil capable of taking in magnetic field energy, the second power receiving resonant circuit having a characteristic of resonating at the second frequency, and to receive magnetic field energy from the power transmitting coil as electric power by means of the second power receiving coil which resonates with the power transmitting coil and enters a resonant state; and

a communication unit configured to receive information of a resonant frequency transmitted from at least one of the first wireless power receiving unit and the second wireless power receiving unit, and to transmit the received information of the resonant frequency to a power transmission control unit,

wherein the power transmission control unit is configured to variably change a resonance characteristic of the variable resonant circuit to the first frequency or the second frequency by transmitting alternating current power which matches a unique resonant frequency of the at least one of the first wireless power receiving unit and the second wireless power receiving unit from the electromagnetic induction coil to the power transmitting coil by an electromagnetic induction according to the information of the resonant frequency transmitted from the communication unit.

6. The wireless power supply system according to claim 5, wherein:

the power transmission control unit, when the communication unit receives a plurality of power transmission requests in an overlapping manner, tunes the alternating current frequency to the resonant frequencies of the corresponding wireless power receiving devices in the order in which the power transmission requests are received or match the resonant frequencies in a cyclical manner by means of time sharing processing.

7. A wireless power transmitting device, comprising:

a variable resonant circuit configured to include a power transmitting coil and have a variable-controllable resonant frequency characteristic;

an electromagnetic induction coil, which is included in the wireless power transmitting device, configured to separate from the power transmitting coil by physical distance;

a communication unit configured to receive information of a resonant frequency transmitted from at least one of a plurality of wireless power receiving devices, and to transmit the received information of the resonant frequency to a power transmission control unit,

wherein the power transmission control unit is configured to variably control the resonant frequency characteristic of the variable resonant circuit by transmitting alternating current power which matches a unique resonant frequency of the at least one of the plurality of wireless power receiving devices from the electromagnetic induction coil to the power transmitting coil by the electromagnetic induction according to the information of the resonant frequency transmitted from the communication unit, and to wirelessly transmit electric power from the power transmitting coil by causing the resonant frequency to tune to a resonant frequency on the at least one of the plurality of wireless power receiving devices to generate a magnetic field resonance mode.

8. The wireless power transmitting device according to claim 7, wherein:

the power transmission control unit, when the communication unit receives a plurality of power transmission requests in an overlapping manner, tunes the alternating current frequency to the resonant frequencies of the corresponding wireless power receiving devices in the order in which the power transmission requests are received or match the resonant frequencies in a cyclical manner by means of time sharing processing.